Percussive rock drill



E. PENBERTHY Arron/vw ISpt. 18, 192s.

- PERoUssIvE R'locx DRILL Filed March 24, 19,27

Patented Sept. `18, A1928.

UNITED STATES PATENT foFFicE; f

ERNEST PENBERTHY, OF REDRUTH, CORNVVALL, ENG-LAND, ASSIGNOR TO THE CLIIVIAX` ROCK DRILL & ENGINEERING WORKS LIMITED, G13 LONDON, ENGLAND, A COMPANY OF GREAT BRITAIN.

Application filed March 24, 1927, serialiy No.

This invention relates to percussive rock drills has for its object to provide animproved form of valve for such drills. Y

According to the present invention the valve member is provided with two spools or shoulders adaptedtov cooperate with ports in the cylinder of the hammer pistoiithat after the valve has been fully moved into a position to disconnect the supply of liveair to one end of the hammer piston and to open the supply of live'air to the other end ot the hammer piston, live air is caused to act on one -of the valve spools or shoulders so as to move the valve into a mid-Way position so that live air onV its end may complete its travel until the hammer piston reaches the end oi the stroke when the operation of the valve is repeated. The valve chamber may also be provided with vents' sodas to preiiiit of escape of any air Which may leak along the valve body. The

ends of the valves are adapted, iii their end positions to be seated in valve bushings provided with seats circum'erentially engaging f with the circular portion of the valve body, and with a seat against which the face of the valve body is adapted to bear. L

Tivo forms of construction in accordance with the invention are illustrated in the accompanying drawings Whereinz*q Figure 1 shows a longitudinal section of a percussive rock drill.

Figure 2 shoivs a longitudinal sectionof the valve.

Figure 3 shows a section on the line 3;-3 of Figure 1 and Figure 4 shows a longitudinal section of a modified iorm of valve mechanism applied to a percussive rock drill.

' According to the one example of construction shown in Figures 1-3 the valve con sists of a tubular body 1 having a partition 2 arranged at the centre and extending diainetrically across it. 0n the tubular body are formed two spools or shoulders 3, 4, Which are adapted to co-operate with two annular grooves 5, 6, on the inner face of the valve chamber 7, and communicating With tivo exhaust ports 8, 9, `in thecylinder 10 of the hammer piston llivhich cylinder 10 is also provided with two internal annular grooves 42, 43 communicatingV respectively With the exhaust ports 8, 9. The tubular ends of the valve body `1 are adapted 'to con- PERCUSSIVE ROCK DRILL.

178,023, and in Great Britain April 21, 1926.

trol the supply of live air to the opposite ends ofthe hammer piston 11 movably mounted in the cylinder 10; The valve` casing? is pro-y vided with ports 12, 13'Which are connected by passages 14, 15 to the exhaust ports 9. 8. of the cylinder, the arrangement being such that the port 12 at the left-hand end of the valve chamber 7 communicates with the exhaust port 9 near the ri ight-hand end of the cylinder 10, Whilst the port 13 at the right-hand end of the valve chamber 7 communicates With theexhaust port 8 of the cyliiil der 10 near the left hand end of the latter. Y is provided with an inlet port 16 fory the live air, and an exhaust port 17.

The tubular ends of the valve are guided in circular members 18, 19 formed integral With end bushings 20, 21, and these circular members 18, 19 are each provided With an internal annular groove 22, 23 normally communi-` cating with the atmosphere by means of one s or more vent h oles 2a so as to perinit'o the escape of any leakage ot air from opposite sides oi said circular members 18, 19.

Circumiieiential seatings 25 and end seat,

ings .26 ior the valve are provided in the end bushings 20, 21 which are littedinto the ends of the valve casing 7, and the bushing at one end is held in position and prevented from displacement by a projection 27,1ormed` on the division ring 28 Whichl is located be! tween the cylinder 10 of the hammer piston and the guide 29 for the drill 30. vThe projection 27 of the division ring 28 When in position engages Witha shoulder' portion 31 on the valve bushing 2O and thus prevents any rotation thereof. rlhe valve bushing' 21 at the other end ofthe valve chamber 7 is held in4 position by means oi the cover plate 32 fory rlhe operation of a valve mechanism as above described is as follows:

Assuming that the hammer piston 11 is to be driven in the direction of the arrow 36 to the right-.hand end oi its cylinder 10 and lthe valve member 1 is. at the right-haiidlend The valve chamber of its chamber as shown in Figure 1 live air will pass from the inlet port 16 to the lefthand end of the valvel through the port 87 in the valve bushing to the left-hand end of the hammer piston 11. During its movement to the right the hammer pist-on 11 will uncover the exhaust port 8 so that live air can pass through the passage 15 to the port 13 in the valve chamber 7 to the right of the right-hand collar a, and thus move the valve to the left. NVhen the' valve has reached the middle of its movement to the left it closes the Yinlet port 37to the live air to the lefthand end ot the cylinder 10, and also opens the'port 38 for the admission of live air to the right-handeiid of the hammer piston 11V i thus causing the piston 11 to move to the left. During this operation the same sequence of operations willbe repeated. Y*

The shoulders 3, i ontlie valve control the exhaust "of air from the cylinder 10 of the hammer piston. Then the piston'11 has y reached its lett-handv position, that is` at' the instant when `it strikes the drill steel, the

exhaust port 9 near the right-hand end` of the cylinder 10 communicates by means of the passage 14 with the port 12 at the letthand, end of the valve chamber, and as the area of the shoulder is greater than the area of the end of the valve, against which the air acts when 'the valve is opened, the valve is moved to its mid-position, and air will pass the left-hand end of the valve and enter the left-hand end of the cylinder 1() through the port 37. During this movement the ri glithand shoulder l on the valve body will uncover the exhaust poit 9 at the right hand end of the cylinder so that this will he directly connected to the main exhaust 17.

The small vent holes provided inthe Vspools or shoulders A3, Il of the valve are adapted to serve to scavenge the valve chamy bers alternativel'y7 when pressure is applied at the opposing end through one or other of the exhaust ports ofv the cylinder,

In a modified form of construction (Fig.

,4) the valve 1 is tubular and is not provided with a partition so that in the position o t the valve as shown live air passes through the interior of the valve body 1 to the left-hand end of the cylinder 1() of the hammer piston, whereas when the valve is in its left-hand position the supplyo live air is admitted to the right end of the cylinder, whilstthe admission of the other end of the cylinderis closed b v the valve. In this case the spools or shoulders 3, l are not provided with ventv holes, but vent holes 39 are provided in the circular members 18, 19 which are formed integral with the valve bushings 20, 21 so as to produce the necessary scavenging. The operation of the valve is otherwise the same as that aboveV described in connection with Figures 1 to 3.

' Having thus described our invention what I claim as new and desire to secure by Letters Patent is :-V

1. In a percussive rock drill a cylinder said cylinder having two inlet ports onea-t each end thereof, said cylinder having two exhaust ports spaced apart and intermediate said inlet ports, said cylinder having passages therein, one-passage leading from one exhaust port to Aa point outside said cylinder between the second exhaust port and the in# inlet port in saidvalve chamber `to the inlet ports in said cylinder, said exhaust port in said valve chamber being adapted to be brought alternately into communication with valvemeniber in said valve chamber, said valve member consisting of a tubular iiiembei' and two spools mounted on said tubular member, said tubularv member and spools being adapted to control the passages-oiL said valve chamber and the exhaiistports of said cylinder', said valve chamber having small airvents therein. i

2.1n a percussive `rock drill a cylinder, said cylinder having two inlet'ports one at `the exhaust ports in` saidwcylinder, and Va each end thereof, said cylinder having two exhauStports Yspaced .apart and intermediate said inlet ports, said cylinder having passages therein, one passage leading'from one exhaust portto a point outside said cylinder between the second exhaust port and the inlet port nearest thereto whilst the second passage lea-ds from the second exhaust port to a point outside said cylinder between the first exhaust port andthe inlet port nearest thereto, a hammer piston working in said cylinder,` said hammer piston being" adapted during its operation` to control the openingr and closing ot' said exhaust ports, a valve chamber mounted on said cylinder, said valve chamber having an inlet port and an exhaust port and passages leading from the inlet port iri-saidivalve chamber to the inlet ports in said. cylinder, said exhaust port in said valve chamber being adapted to be brought alternately into communication with the exhaust ports in said cylinder, and a valve member in said valve chamber, said valve member consisting of a tubular member and two spools mounted on said tubular member, said tubular member and spools being adapted to control the passages of said valve `chamber and the exhaust ports of said cylinder, said spools having small vent holes therein for scavenging the portions at the-outer ends of the valve chambers alternately when pressure is applied at the opposing end through one or other` of the exhaust ports of said cylinder.

3. In a pereussive rock drill a cylinder,` said cylinder having two inlet ports one at each end thereof, said cylinder having two exhaustv ports spaced apart and intermediate said inlet ports, said cylinder having pas-V sages therein, one passage leading from one exhaust port to a point outside said cylinder between t-he second exhaust port and the inletport nearest thereto whilst the second passage leads from the second exhaust port to a point outside said cylinder between the first exhaust port and the inlet port nearest thereto, a hammer piston'working in said cylinder, said hammer pist-on being adapted during its operation to control the opening and closing of said exhaust ports, a valve chamber mounted on said cylinder, said valve chamber having an inlet port and an exhaust port and passages leading from ,the inlet port in said valve chamber to the inlet ports in said cylinder, said exhaust port in said valve chamber being' adapted to be brought alternately into communication with the exhaust ports in said cylinder, and a valve member in said valve chamber, said valve member consisting of a tubular member and two spools mounted on said tubular member, said t-ubular member and spools being adapted to control the passages of saidvalve chamber and the exhaust ports of said cylinder, valve bushings in said valve chamber` and circular members formed integral with said valve bushings, said valve chamber and said circular members havingv registering vent holes.

4l. In a percussive rock drill, a cylinder having two inlet ports, one adjacent each end thereof, and two exhaust ports located between said inlet ports, a hammer piston working in said cylinder, a valve chamber mounted on said cylinder, said valve chamber having one inlet port and one exhaust port and passages leadingfrom the inlet port therein to the inlet ports in said cylinder, and a valve member mounted tor to and tre movement in said valve chamber, said valve member consisting of a tubular'member and two spaced spools on said tubular membenone of said spools controlling one of said-cylinder exhaust ports, and 'the second spool controlling the second cylinder exhaust port, the

exhaust port in said valve chamber being` located between said spools, said cylinder having` two passages therein.y one of said passages leadine` from one cylinder exhaust port to a point in the valve chamber adjacent the extreme end position Oli the face olf' t-he spool, controlling' the second cylinder exhaust port, remote from the spool controllimr the tirs-t cylinder exhaust port, whilst the other passage leads from the second cylinder exhaust port to ay point in the valve chamber adjacent the extreme end posit-ion oli' the tace of vthe spool, controlling the first cylinder es haust port,`remote 'l'rointhe spool controlline' the second cvlinder exhaust )ort the hammer piston being;

close said passages leadingl from the cylinder exhaust ports during the moven'ient of said,

spaced spools mounted onl said-tubular member, said spools being; located in the valve chaniber on opposite sides ot the exhaust port in said valve chamber and being adapted. to' control communication between the cylinder exhaustports and the exhaust port in the valve chamber, said cylinderlutving annular grooves in the inner surface thereof and kicker ports in each oi said grooves, said*` cylinder having-passages leading' l'rom the adapted to open and aid` valve `member consistingof a tubular member and tvvo'k kicker ports into said valve chamber, one yof said passagesleading from one kicker'port to beyond the second kickerport and to a point in said valve chamber adjacent the end position of one spool, whilst the second pas- A saeje leads 'from the vsecond kicker port to beyond the first kicker port and to a point in said valvechamber adjacent the end position of the second spool.

6. In a percussive rock drill, a cylinder having' two inlet ports, one adjacent-each end A thereof, and two exhaust Vports located between said inletports, a hammer piston'working` in said cylinder, a valve chamber mount-- ed on said cylinder, said valve chamber hav-- y ing one inlet port and one e-haust port and passages leading' from the inlet port therein to the inlet ports in said'cylinder, and a va lvo member mounted for to and fro movement in said valve chamber, said valve member consisting oil a tubular member and two spaced spools mounted on said tubular member, said spools beine' located in the valve chamber on valve chamber and being; adapted to control communication between the cylinder exhaust ports and the exhaust port in the valve chamber, said cylinder having' annular grooves in the inner surface thereotl and kicker ports in each oit said grooves, said cylinder having passages leading from the kicker ports into said valve chamber, one el said passages leading from one kicker port to beyond the second kicker port and to a point in said valve chamopposite sides of the exhaust port in said V120 ber adjacent the end position of one spool, whilst thesecond passage leads from the sec ond kicker portto beyond the first kicker port and to a point in said valve chamber adjacent the end position of the second spoohsaid valve chamber having annular grooves in the interior thereof, each of said grooves communicating with Aone of the exhaust ports in said cylinder. Y

7. In a percussive rock drill, a cylinder having two inlet ports, one adjacent each end thereof, and two exhaust ports located between said inlet ports, a hammer piston workn ing in said cylinder, a valve chamber mounted on said cylinder, said valve chamber having one `inlet port and one izhaust port and passagesleading from theinlet port therein to the inlet ports in said cylinder, and a vulve mer ber mounted for to and fro movement in s ,i valve chamber, said valve member consisting of a tubularmember and two spaced spools mounted on said tubular member, said spools? being located in the valve chamber on oppesite sides of the exhaust port in said valve chamber and being adapted to control coinmunication between the cylinder i exhaust orts andthe exhaust port in the valve chamer, said cylinder having annulargrooves in he inner surface thereoil and kicker ports in each of saidgrooves, said cylinder having passages leading from the kicker ports inte said valve chamber, one oi said passages lead ing from one kicker port to bC/Ond the second kicker port and to a point in said valve chamber adjacent the end position of one spool, whilst the second passage leads from the second kicker port to beyond the lfirst kicker port and to a point m said'valve chamber adjacent the end position of the second spool, andvalve bushings fitted in the ends of said valveV chamber, said valve bushings having seats adapted to engage circumferentially with the endsof the tubular member, and seats against which the end vraces ofthe tubular member are adapted to bear. i

8. In a percussive rock drill a cylinder, said cylinder having two inlet ports, one at each end thereof, and two exhaust ports spaced` apart and intermediate said inlet ports, said integral with said bushings, said circular,`

member having annular grooves therein and vent holes in communication therewith, a tubular member mounted for to andfro movement in said-valve chamber, two spaced spools mounted on said tubular member, said spaced .spools being located in said valve chamber on opposite sides Aof the exhaust port in said valve chamber-and adapted to seat against the circular members, whilst the.

tubular portions of the tubular member beyond the spools'arc adapted to controlthe passages leading from the inlet port in theV valve chamber to the inlet portsin said cylindcr, said valve chamber having internal annular grooves communicating onel with each ot the exhaustports `in said cylinder, said cylinder having two passages therein,

one of said passages leading from one kickerA port lto beyond the second kicker port and to a point adjacent the seating face of one circular member, whilst the other passage leads from the second kicker port to beyond the first kicker port and to a point adjacent the seating of the second circular member, anda hammer piston working in said cylinder, the arrangement being such that the hammer piston exposes the kickerports for the purpose of enabling the valve member to be actuated whilst the valve member when actuated controls the passagesleading tothe inlet ports of said cylinders andsaid valve member also controlling the exhaust ports of` said cylinder and a diametral partition in said tubular member in a position mid-Way between said spools.

ERNEST PENBERTHY. 

